java.lang.Object
- com.mckoi.database.TransactionSystem

Direct Known Subclasses:

DatabaseSystem
```
public class TransactionSystem
extends java.lang.Object
```
A class that provides information and global functions for the transaction layer in the engine. Shared information includes configuration details, logging, etc.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`private static class`	`TransactionSystem.DSFunctionLookup`	A FunctionLookup implementation that will look up a function from a list of FunctionFactory objects provided with.

Field Summary

Fields
Modifier and Type	Field	Description
`private boolean`	`always_reindex_dirty_tables`	If this is set to true, during boot up the engine will reindex all the tables that weren't closed.
`private LoggingBufferManager`	`buffer_manager`	A LoggingBufferManager object used to manage pages of ScatteringFileStore objects in the file system.
`private DBConfig`	`config`	The ResourceBundle that contains properties of the entire database system.
`private DataCellCache`	`data_cell_cache`	The DataCellCache that is a shared resource between on database's.
`private java.io.File`	`db_path`	The path in the file system for the database files.
`private DatabaseDispatcher`	`dispatcher`	The dispatcher.
`private boolean`	`dont_synch_filesystem`	Set to true if the file handles should NOT be synchronized with the system file IO when the indices are written.
`private java.util.ArrayList`	`function_factory_list`	The list of FunctionFactory objects that handle different functions from SQL.
`private TransactionSystem.DSFunctionLookup`	`function_lookup`	The FunctionLookup object that can resolve a FunctionDef object to a Function object.
`private boolean`	`ignore_case_for_identifiers`	Set to true if the parser should ignore case when searching for a schema, table or column using an identifier.
`private java.io.File`	`log_directory`	The log directory.
`private DefaultDebugLogger`	`logger`	A logger to output any debugging messages.
`private boolean`	`lookup_comparison_list_enabled`	Set to true if lookup comparison lists are enabled.
`private boolean`	`read_only_access`	Set to true if the database is in read only mode.
`private RegexLibrary`	`regex_library`	The regular expression library bridge for the library we are configured to use.
`private boolean`	`soft_index_storage`	Set to false if there is conservative index memory storage.
`private Stats`	`stats`	The stats object that keeps track of database statistics.
`private StoreSystem`	`store_system`	The underlying StoreSystem implementation that encapsulates the behaviour for storing data persistantly.
`private java.util.ArrayList`	`table_listeners`	A list of table names and listeners that are notified of add and remove events in a table.
`private boolean`	`table_lock_check`	Set to true if locking checks should be performed each time a table is accessed.
`private boolean`	`transaction_error_on_dirty_select`	Transaction option, if this is true then a transaction error is generated during commit if a transaction selects data from a table that has committed changes to it during commit time.

Constructor Summary

Constructors
Constructor Description

TransactionSystem()
Constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addFunctionFactory(FunctionFactory factory)`	Registers a new FunctionFactory with the database system.
`boolean`	`alwaysReindexDirtyTables()`	Returns the status of the 'always_reindex_dirty_tables' property.
`(package private) java.lang.Object`	`createEvent(java.lang.Runnable runnable)`	Creates an event object that is passed into 'postEvent' method to run the given Runnable method after the time has passed.
`DebugLogger`	`Debug()`	Returns the DebugLogger object that is used to log debug message.
`void`	`dispose()`	Disposes this object.
`boolean`	`dontSynchFileSystem()`	Returns true if we shouldn't synchronize with the file system when important indexing information is flushed to the disk.
`void`	`flushCachedFunctionLookup()`	Flushes the 'FunctionLookup' object returned by the getFunctionLookup method.
`LoggingBufferManager`	`getBufferManager()`	Returns the LoggingBufferManager object enabling us to create no file stores in the file system.
`boolean`	`getConfigBoolean(java.lang.String property, boolean default_val)`	Returns a configuration value, or the default if it's not found.
`int`	`getConfigInt(java.lang.String property, int default_val)`	Returns a configuration value, or the default if it's not found.
`java.lang.String`	`getConfigString(java.lang.String property, java.lang.String default_val)`	Returns a configuration value, or the default if it's not found.
`java.io.File`	`getDatabasePath()`	Returns the path of the database in the local file system if the database exists within the local file system.
`(package private) DataCellCache`	`getDataCellCache()`	Returns a DataCellCache object that is a shared resource between all database's running on this VM.
`private DatabaseDispatcher`	`getDispatcher()`	Returns the DatabaseDispatcher object.
`FunctionLookup`	`getFunctionLookup()`	Returns a FunctionLookup object that will search through the function factories in this database system and find and resolve a function.
`java.io.File`	`getLogDirectory()`	Returns the current log directory or null if no logging should occur.
`RegexLibrary`	`getRegexLibrary()`	Returns the regular expression library from the configuration file.
`boolean`	`ignoreIdentifierCase()`	Returns true if the parser should ignore case when searching for schema/table/column identifiers.
`void`	`init(DBConfig config)`	Inits the TransactionSystem with the configuration properties of the system.
`boolean`	`lookupComparisonListEnabled()`	Returns true if we should generate lookup caches in InsertSearch otherwise returns false.
`private static java.io.File`	`parseFileString(java.io.File root_path, java.lang.String root_info, java.lang.String path_string)`	Parses a file string to an absolute position in the file system.
`(package private) void`	`postEvent(int time_to_wait, java.lang.Object event)`	Adds a new event to be dispatched on the queue after 'time_to_wait' milliseconds has passed.
`Transaction.CheckExpression`	`prepareTransactionCheckConstraint(DataTableDef table_def, Transaction.CheckExpression check)`	Given a Transaction.CheckExpression, this will prepare the expression and return a new prepared CheckExpression.
`boolean`	`readOnlyAccess()`	Returns true if the database is in read only mode.
`private static java.lang.String`	`regexStringToClass(java.lang.String lib)`	Given a regular expression string representing a particular library, this will return the name of the class to use as a bridge between the library and Mckoi.
`void`	`setDebugLevel(int level)`	Sets the debug minimum level that is output to the logger.
`void`	`setDebugOutput(java.io.Writer writer)`	Sets the Writer output for the debug logger.
`void`	`setLogDirectory(java.io.File log_path)`	Sets the log directory.
`private void`	`setupLog(DBConfig config)`	Sets up the log file from the config information.
`void`	`setupRowCache(int max_cache_size, int max_cache_entry_size)`	Hack - set up the DataCellCache in DatabaseSystem so we can use the MasterTableDataSource object without having to boot a new DatabaseSystem.
`boolean`	`softIndexStorage()`	Returns true if all table indices are kept behind a soft reference that can be garbage collected.
`Stats`	`stats()`	Returns a com.mckoi.util.Stats object that can be used to keep track of database statistics for this VM.
`StoreSystem`	`storeSystem()`	Returns the StoreSystem encapsulation being used in this database.
`boolean`	`tableLockingEnabled()`	Returns true if the database should perform checking of table locks.
`boolean`	`transactionErrorOnDirtySelect()`	Returns true if during commit the engine should look for any selects on a modified table and fail if they are detected.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - stats
```
private final Stats stats
```
    The stats object that keeps track of database statistics.
  - logger
```
private final DefaultDebugLogger logger
```
    A logger to output any debugging messages. NOTE: This MUST be final, because other objects may retain a reference to the object. If it is not final, then different objects will be logging to different places if this reference is changed.
  - config
```
private DBConfig config
```
    The ResourceBundle that contains properties of the entire database system.
  - db_path
```
private java.io.File db_path
```
    The path in the file system for the database files. Note that this will be null if the database does not exist in a local file system. For this reason it's best not to write code that relies on the use of this value.
  - lookup_comparison_list_enabled
```
private boolean lookup_comparison_list_enabled
```
    Set to true if lookup comparison lists are enabled.
  - read_only_access
```
private boolean read_only_access
```
    Set to true if the database is in read only mode. This is set from the configuration file.
  - table_lock_check
```
private boolean table_lock_check
```
    Set to true if locking checks should be performed each time a table is accessed.
  - soft_index_storage
```
private boolean soft_index_storage
```
    Set to false if there is conservative index memory storage. If true, all root selectable schemes are stored behind a soft reference that will be garbage collected.
  - always_reindex_dirty_tables
```
private boolean always_reindex_dirty_tables
```
    If this is set to true, during boot up the engine will reindex all the tables that weren't closed. If false, the engine will only reindex the tables that have unchecked in modifications.
  - dont_synch_filesystem
```
private boolean dont_synch_filesystem
```
    Set to true if the file handles should NOT be synchronized with the system file IO when the indices are written. If this is true, then the database is not as fail safe, however File IO performance is improved.
  - ignore_case_for_identifiers
```
private boolean ignore_case_for_identifiers
```
    Set to true if the parser should ignore case when searching for a schema, table or column using an identifier.
  - transaction_error_on_dirty_select
```
private boolean transaction_error_on_dirty_select
```
    Transaction option, if this is true then a transaction error is generated during commit if a transaction selects data from a table that has committed changes to it during commit time.
    True by default.
  - data_cell_cache
```
private DataCellCache data_cell_cache
```
    The DataCellCache that is a shared resource between on database's.
  - function_factory_list
```
private java.util.ArrayList function_factory_list
```
    The list of FunctionFactory objects that handle different functions from SQL.
  - function_lookup
```
private TransactionSystem.DSFunctionLookup function_lookup
```
    The FunctionLookup object that can resolve a FunctionDef object to a Function object.
  - regex_library
```
private RegexLibrary regex_library
```
    The regular expression library bridge for the library we are configured to use.
  - log_directory
```
private java.io.File log_directory
```
    The log directory.
  - buffer_manager
```
private LoggingBufferManager buffer_manager
```
    A LoggingBufferManager object used to manage pages of ScatteringFileStore objects in the file system. We can configure the maximum pages and page size via this object, so we have control over how much memory from the heap is used for buffering.
  - store_system
```
private StoreSystem store_system
```
    The underlying StoreSystem implementation that encapsulates the behaviour for storing data persistantly.
  - table_listeners
```
private java.util.ArrayList table_listeners
```
    A list of table names and listeners that are notified of add and remove events in a table.
  - dispatcher
```
private DatabaseDispatcher dispatcher
```
    The dispatcher.
- Constructor Detail
  - TransactionSystem
```
public TransactionSystem()
```
    Constructor.
- Method Detail
  - parseFileString
```
private static java.io.File parseFileString(java.io.File root_path,
                                            java.lang.String root_info,
                                            java.lang.String path_string)
```
    Parses a file string to an absolute position in the file system. We must provide the path to the root directory (eg. the directory where the config bundle is located).
  - setupLog
```
private void setupLog(DBConfig config)
```
    Sets up the log file from the config information.
  - getConfigString
```
public final java.lang.String getConfigString(java.lang.String property,
                                              java.lang.String default_val)
```
    Returns a configuration value, or the default if it's not found.
  - getConfigInt
```
public final int getConfigInt(java.lang.String property,
                              int default_val)
```
    Returns a configuration value, or the default if it's not found.
  - getConfigBoolean
```
public final boolean getConfigBoolean(java.lang.String property,
                                      boolean default_val)
```
    Returns a configuration value, or the default if it's not found.
  - regexStringToClass
```
private static java.lang.String regexStringToClass(java.lang.String lib)
```
    Given a regular expression string representing a particular library, this will return the name of the class to use as a bridge between the library and Mckoi. Returns null if the library name is invalid.
  - init
```
public void init(DBConfig config)
```
    Inits the TransactionSystem with the configuration properties of the system. This can only be called once, and should be called at database boot time.
  - setupRowCache
```
public void setupRowCache(int max_cache_size,
                          int max_cache_entry_size)
```
    Hack - set up the DataCellCache in DatabaseSystem so we can use the MasterTableDataSource object without having to boot a new DatabaseSystem.
  - readOnlyAccess
```
public boolean readOnlyAccess()
```
    Returns true if the database is in read only mode. In read only mode, any 'write' operations are not permitted.
  - getDatabasePath
```
public java.io.File getDatabasePath()
```
    Returns the path of the database in the local file system if the database exists within the local file system. If the database is not within the local file system then null is returned. It is recommended this method is not used unless for legacy or compatability purposes.
  - tableLockingEnabled
```
public boolean tableLockingEnabled()
```
    Returns true if the database should perform checking of table locks.
  - lookupComparisonListEnabled
```
public boolean lookupComparisonListEnabled()
```
    Returns true if we should generate lookup caches in InsertSearch otherwise returns false.
  - softIndexStorage
```
public boolean softIndexStorage()
```
    Returns true if all table indices are kept behind a soft reference that can be garbage collected.
  - alwaysReindexDirtyTables
```
public boolean alwaysReindexDirtyTables()
```
    Returns the status of the 'always_reindex_dirty_tables' property.
  - dontSynchFileSystem
```
public boolean dontSynchFileSystem()
```
    Returns true if we shouldn't synchronize with the file system when important indexing information is flushed to the disk.
  - transactionErrorOnDirtySelect
```
public boolean transactionErrorOnDirtySelect()
```
    Returns true if during commit the engine should look for any selects on a modified table and fail if they are detected.
  - ignoreIdentifierCase
```
public boolean ignoreIdentifierCase()
```
    Returns true if the parser should ignore case when searching for schema/table/column identifiers.
  - getBufferManager
```
public LoggingBufferManager getBufferManager()
```
    Returns the LoggingBufferManager object enabling us to create no file stores in the file system. This provides access to the buffer scheme that has been configured.
  - getRegexLibrary
```
public RegexLibrary getRegexLibrary()
```
    Returns the regular expression library from the configuration file.
  - storeSystem
```
public final StoreSystem storeSystem()
```
    Returns the StoreSystem encapsulation being used in this database.
  - setDebugOutput
```
public final void setDebugOutput(java.io.Writer writer)
```
    Sets the Writer output for the debug logger.
  - setDebugLevel
```
public final void setDebugLevel(int level)
```
    Sets the debug minimum level that is output to the logger.
  - Debug
```
public final DebugLogger Debug()
```
    Returns the DebugLogger object that is used to log debug message. This method must always return a debug logger that we can log to.
  - addFunctionFactory
```
public void addFunctionFactory(FunctionFactory factory)
```
    Registers a new FunctionFactory with the database system. The function factories are used to resolve a function name into a Function object. Function factories are checked in the order they are added to the database system.
  - flushCachedFunctionLookup
```
public void flushCachedFunctionLookup()
```
    Flushes the 'FunctionLookup' object returned by the getFunctionLookup method. This should be called if the function factory list has been modified in some way.
  - getFunctionLookup
```
public FunctionLookup getFunctionLookup()
```
    Returns a FunctionLookup object that will search through the function factories in this database system and find and resolve a function. The returned object may throw an exception from the 'generateFunction' method if the FunctionDef is invalid. For example, if the number of parameters is incorrect or the name can not be found.
  - prepareTransactionCheckConstraint
```
public Transaction.CheckExpression prepareTransactionCheckConstraint(DataTableDef table_def,
                                                                     Transaction.CheckExpression check)
```
    Given a Transaction.CheckExpression, this will prepare the expression and return a new prepared CheckExpression. The default implementation of this is to do nothing. However, a sub-class of the system choose to prepare the expression, such as resolving the functions via the function lookup, and resolving the sub-queries, etc.
  - stats
```
public final Stats stats()
```
    Returns a com.mckoi.util.Stats object that can be used to keep track of database statistics for this VM.
  - setLogDirectory
```
public final void setLogDirectory(java.io.File log_path)
```
    Sets the log directory. This should preferably be called during initialization. If the log directory is not set or is set to 'null' then no logging to files occurs.
  - getLogDirectory
```
public final java.io.File getLogDirectory()
```
    Returns the current log directory or null if no logging should occur.
  - getDataCellCache
```
DataCellCache getDataCellCache()
```
    Returns a DataCellCache object that is a shared resource between all database's running on this VM. If this returns 'null' then the internal cache is disabled.
  - getDispatcher
```
private DatabaseDispatcher getDispatcher()
```
    Returns the DatabaseDispatcher object.
  - createEvent
```
java.lang.Object createEvent(java.lang.Runnable runnable)
```
    Creates an event object that is passed into 'postEvent' method to run the given Runnable method after the time has passed.
    The event created here can be safely posted on the event queue as many times as you like. It's useful to create an event as a persistant object to service some event. Just post it on the dispatcher when you want it run!
  - postEvent
```
void postEvent(int time_to_wait,
               java.lang.Object event)
```
    Adds a new event to be dispatched on the queue after 'time_to_wait' milliseconds has passed.
    'event' must be an event object returned via 'createEvent'.
  - dispose
```
public void dispose()
```
    Disposes this object.

Class TransactionSystem

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

stats

logger

config

db_path

lookup_comparison_list_enabled

read_only_access

table_lock_check

soft_index_storage

always_reindex_dirty_tables

dont_synch_filesystem

ignore_case_for_identifiers

transaction_error_on_dirty_select

data_cell_cache

function_factory_list

function_lookup

regex_library

log_directory

buffer_manager

store_system

table_listeners

dispatcher

Constructor Detail

TransactionSystem

Method Detail

parseFileString

setupLog

getConfigString

getConfigInt

getConfigBoolean

regexStringToClass

init

setupRowCache

readOnlyAccess

getDatabasePath

tableLockingEnabled

lookupComparisonListEnabled

softIndexStorage

alwaysReindexDirtyTables

dontSynchFileSystem

transactionErrorOnDirtySelect

ignoreIdentifierCase

getBufferManager

getRegexLibrary

storeSystem

setDebugOutput

setDebugLevel

Debug

addFunctionFactory

flushCachedFunctionLookup

getFunctionLookup

prepareTransactionCheckConstraint

stats

setLogDirectory

getLogDirectory

getDataCellCache

getDispatcher

createEvent

postEvent

dispose